https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89781
Bug ID: 89781
Summary: Misleading error messages when initializing a static
data member in-class
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: redbeard0531 at gmail dot com
Target Milestone: ---
The error messages make sense in a pre-c++17 world before inline variables
existed. Now they are lies!
struct X{};
struct Y { static X x = {}; };
<source>:2:21: error: 'constexpr' needed for in-class initialization of static
data member 'X Y::x' of non-integral type [-fpermissive]
struct Y { static X x = {}; };
^
The error is even worse when X can't be a constexpr variable:
struct X{ X(); };
struct Y { static X x = {}; };
<source>:2:21: error: in-class initialization of static data member 'X Y::x' of
non-literal type
struct Y { static X x = {}; };
^
<source>:2:26: error: temporary of non-literal type 'X' in a constant
expression
struct Y { static X x = {}; };
^
<source>:1:8: note: 'X' is not literal because:
struct X{ X(); };
^
<source>:1:8: note: 'X' is not an aggregate, does not have a trivial default
constructor, and has no 'constexpr' constructor that is not a copy or move
constructor
This compiles just fine:
struct X{ X(); };
struct Y { static inline X x = {}; };
All examples were passing -std=c++17.
